Abstract
Iron deficiency in higher plants causes accumulation of salts of organic acids in the roots, the most characteristic being citrate. We show that citrate and malate accumulate in beans (Phaseolus vulgaris L. var Prélude), not because of a lack of the iron-containing enzyme aconitase (EC 4.2.1.3), but in close coupling to the extrusion of protons during rhizosphere acidification, one of the `Fe-efficiency' reactions of dicotyledonous plants. When proton excretion is induced in roots of control bean plants by addition of fusicoccin, only malate, not citrate, is accumulated. We propose that iron deficiency induces production of organic acids in the roots, which in beans leads to both proton excretion and an increased capacity to reduce ferric chelates via the induced electron transfer system in the root epidermis cells.
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- BACON J. S., DEKOCK P. C., PALMER M. J. Aconitase levels in the leaves of iron-deficient mustard plants (Sinapis alba). Biochem J. 1961 Jul;80:64–70. doi: 10.1042/bj0800064. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bienfait H. F. Regulated redox processes at the plasmalemma of plant root cells and their function in iron uptake. J Bioenerg Biomembr. 1985 Apr;17(2):73–83. doi: 10.1007/BF00744199. [DOI] [PubMed] [Google Scholar]
- Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
- Chaney R. L., Brown J. C., Tiffin L. O. Obligatory reduction of ferric chelates in iron uptake by soybeans. Plant Physiol. 1972 Aug;50(2):208–213. doi: 10.1104/pp.50.2.208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- King R. W., Zeevaart J. A. Enhancement of Phloem exudation from cut petioles by chelating agents. Plant Physiol. 1974 Jan;53(1):96–103. doi: 10.1104/pp.53.1.96. [DOI] [PMC free article] [PubMed] [Google Scholar]
- La Nauze J. M. Aconitase and isocitric dehydrogenases of Aspergillus niger in relation to citric acid production. J Gen Microbiol. 1966 Jul;44(1):73–81. doi: 10.1099/00221287-44-1-73. [DOI] [PubMed] [Google Scholar]
- Ma H., Kubicek C. P., Röhr M. Metabolic effects of manganese deficiency in Aspergillus niger: evidence for increased protein degradation. Arch Microbiol. 1985 Apr;141(3):266–268. doi: 10.1007/BF00408070. [DOI] [PubMed] [Google Scholar]
- RACKER E. Spectrophotometric measurements of the enzymatic formation of fumaric and cis-aconitic acids. Biochim Biophys Acta. 1950 Jan;4(1-3):211–214. doi: 10.1016/0006-3002(50)90026-6. [DOI] [PubMed] [Google Scholar]
- Römheld V., Marschner H. Evidence for a specific uptake system for iron phytosiderophores in roots of grasses. Plant Physiol. 1986 Jan;80(1):175–180. doi: 10.1104/pp.80.1.175. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Römheld V., Marschner H. Mechanism of iron uptake by peanut plants : I. Fe reduction, chelate splitting, and release of phenolics. Plant Physiol. 1983 Apr;71(4):949–954. doi: 10.1104/pp.71.4.949. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Römheld V., Müller C., Marschner H. Localization and capacity of proton pumps in roots of intact sunflower plants. Plant Physiol. 1984 Nov;76(3):603–606. doi: 10.1104/pp.76.3.603. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tiffin L. O. Iron Translocation II. Citrate/Iron Ratios in Plant Stem Exudates. Plant Physiol. 1966 Mar;41(3):515–518. doi: 10.1104/pp.41.3.515. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tiffin L. O. Iron translocation I. Plant culture, exudate sampling, iron-citrate analysis. Plant Physiol. 1966 Mar;41(3):510–514. doi: 10.1104/pp.41.3.510. [DOI] [PMC free article] [PubMed] [Google Scholar]